4.1 Identify the water-heating system above - NSC Civil Technology Civil Services - Question 4 - 2019 - Paper 1
Question 4
4.1 Identify the water-heating system above.
4.1.2 What will be the result of continuous use of hot water from this system?
4.1.3 Why must the glass panel of this ... show full transcript
Worked Solution & Example Answer:4.1 Identify the water-heating system above - NSC Civil Technology Civil Services - Question 4 - 2019 - Paper 1
Step 1
Identify the water-heating system above.
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Answer
The water-heating system is a solar geyser system, commonly known as a solar panel with a geyser integrated for heating water.
Step 2
What will be the result of continuous use of hot water from this system?
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Answer
Continuous use of hot water from this system can lead to a drop in temperature, as the water may eventually cool down if there is inadequate sunlight or heating input.
Step 3
Why must the glass panel of this system be cleaned regularly?
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The glass panel must be cleaned regularly to ensure maximum efficiency in capturing sunlight and to prevent dirt accumulation that can block solar energy absorption.
Step 4
Briefly explain an airlock in a hot-water system.
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An airlock is a condition where air is trapped inside a pipe, preventing the flow of water. This typically happens if there are leaks or insufficient water pressure.
Step 5
State TWO causes of water hammer.
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Sudden changes in water flow, typically from rapid valve closure.
Pipes that are not adequately secured within the building structure.
Step 6
Draw the following symbols:
4.5.1 Mixer (single manual control, single lever)
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Step 7
4.5.2 Vacuum relief valve combined with an air release valve.
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Step 8
Identify the type of water trap.
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The type of water trap shown is an S-Trap.
Step 9
Name the minimum diameter of the waste pipe that connects to the water trap.
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The minimum diameter of the waste pipe that connects to the water trap should be 40mm.
Step 10
Identify the pipe fittings in A and B above.
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A is a T Junction (Plain), and B is a 90° bend with an inspection eye.
Step 11
State where you would install EACH of the pipe fittings in A and B.
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A would be installed where soil pipes meet at the same diameter, while B would be installed above ground where pipes change direction at a 90° angle.
Step 12
Recommend ONE tool that can be used: 4.8.1 To thread and cut pipes
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A pipe-thread cutting machine can be used to thread and cut pipes.
Step 13
4.8.2 For pressure testing of water systems
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A water pressure testing pump is recommended for pressure testing of water systems.
Step 14
4.8.3 To clean and unblock drains using high water pressure.
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A drain-cleaning machine or jetting machine can be utilized for unblocking drains using high water pressure.
Step 15
Identify the tap in FIGURE 4.11 above.
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The tap shown in Figure 4.11 is a pillar tap.
Step 16
Recommend TWO places where you could use this tap.
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Sinks in the kitchen.
Baths or bathrooms.
Step 17
Local authorities use A to determine the water usage of a household. What is this fitting called?
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This fitting is called a water meter.
Step 18
Identify B and explain what the function of this fitting is.
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B is a full-way valve/stop cock, which is used to shut off the water supply to a household.
Step 19
Name the type of tap that is used at C.
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The tap used at C is a bibcock or garden tap.
Step 20
Predict if a chemical reaction will take place if a high-density polyethylene pipe is connected to A.
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No significant chemical reaction will take place since polyethylene is chemically inert and resistant to galvanic corrosion.
Step 21
What is the electrochemical reaction called when zinc is selectively leached from copper pipes?
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The process is termed dezincification.
Step 22
Name TWO water-saving devices that can reduce water waste due to taps that are left open when water supply is shut down and restored later.
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Sensor taps.
Demand pillar taps.
Step 23
Differentiate between a pressure-control valve and temperature and pressure safety valve in terms of its use.
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A pressure-control valve is used to regulate pressure in a system, whereas a temperature and pressure safety valve functions to release pressure when both temperature and pressure exceed predetermined levels, ensuring safety.
